add main

// How to use groovy in Java 1.6 with ScriptEngine
// just for POC purposes

import javax.script.ScriptContext;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;
import java.util.Arrays;
import java.util.List;


class Customer {
    Customer(String name, String code, Integer value) {
        this.name = name;
        this.code = code;
        this.value = value;
    }

    String name;
    String code;
    Integer value;
}

public class Main {
    public static void main(String[] args) throws ScriptException {
        List<Customer> customers = Arrays.asList( new Customer[]{
           new Customer("A","123",1),
           new Customer("B","456",2),
           new Customer("C","789",3),
           new Customer("D","012",4)
        });

        setVariable(customers, "list");
        evaluate("names = list.collect { it.name } ");
        List<String> names = (List<String>) getVariable("names");
        System.out.println("names = " + names);
    }

    // Bunch of helper methods, just to make the above code
    // more readable, not necessarily more efficient

    private static Object getVariable(String name) {
        return groovy().getContext().getAttribute(name);
    }

    private static void evaluate(String script) throws ScriptException {
        groovy().eval(script, groovy().getContext());
    }

    private static void setVariable(List<Customer> customers, String varName) {
        groovy().getContext().setAttribute(varName, customers, ScriptContext.ENGINE_SCOPE);
    }

    private static ScriptEngine groovyEngine;
    private static ScriptEngine groovy() {
        if( groovyEngine == null  ){
            groovyEngine = new ScriptEngineManager().getEngineByName("Groovy");
        }
        return groovyEngine;
    }
}